1. Field of the Invention
This invention relates generally to high peak power oscillating signals, and particularly to a high power microwave device.
2. Description of the Prior Art
As electronic devices and microwave devices in particular become more sophisticated, and are applied to more applications, more power is increasingly desired. The Gunn-effect diode is used to produce oscillating signals due to the periodic nucleation and disappearance of traveling space-charge instability domains. The Gunn-effect diode is made of an n-type GaAs, gallium arsenide, material. N-type gallium arsenide material has free electrons ranging from 10.sup.14 to 10.sup.17 per cubic centimeter at room temperature.
Two references that disclose the use of semiconductors to provide an oscillation of current are, J. B. Gunn, "Microwave Oscillation of Current in III-V Semiconductors", Solid State Communications, Vol. 1, pp 88-91, 1963; and R. Pastore and M. Weiner, "RF Oscillation in Optically Activated GaAs", Record of 7th IEEE Pulse Power Conference, Jun. 1989, pp 872-874. In the R. Pastore and M. Weiner article, a cavity is used to couple the gallium arsenide to the cavity fields. Therefore, the frequency is determined by the cavity adjustment, and the device operates as an oscillator.
While these semiconductor devices for producing oscillation of current resulted in devices useful for their intended purpose, they are not suitable for all applications. In the n-type gallium arsenide devices, power is limited by the voltage hold off capabilities of the n-type gallium arsenide. Additionally, n-type gallium arsenide devices have a high dark current due to relatively high concentration of free electrons. When high power is desired, and high input voltage used, high dark currents are induced resulting in undesirable thermal heating effects. The undesirable thermal heating effects will eventually lead to thermal runaway, and a destruction of the device.
Therefore, there is a need for an improved high power device for amplifying a signal.